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Thomas Library

Honors Thesis Archive

Author Heidi Wollaeger
Title Genetic Variability in Magnolia acuminata (L.) Populations in the Eastern United States
Department Biology
Advisors Matthew Collier, John Ritter, and Michelle McWhorter
Year 2011
Honors University Honors
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Abstract Genetic Variability in Magnolia acuminata (L.) Populations in the Eastern United States Heidi Wollaeger The goal of this study was to use nuclear (ITS1, microsatellites) and chloroplast (psbK-psbI; atpF-atpH; and ndhf-rpl32) regions to determine the population genetics of Magnolia acuminata, commonly known as the cucumber tree, in the eastern United States and to correlate morphological variation with these genetic markers. DNA was extracted with Qiagen DNeasy® kits from samples of M. acuminata provided by the Magnolia Society from populations in the eastern United States. Polymerase chain reactions were performed according to the optimal temperature as determined by the touchdown PCR. The PCR product was electrophoresed in a 1.5% agarose gel stained with ethidium bromide in order to assess DNA sequence size and quality after the amplification. The PCR products for the chloroplast spacer regions (psbK-psbI; atpF-atpH; and ndhf-F-rpl32-R) were Exo-Sapped and cycle sequenced. This product was run through hydrated sephadex plates to purify the sample and was sequenced on a 3730xl DNA Analyzer. The sequences were aligned with Geneious® software. For microsatellite regions stm200 and stm49, the PCR product was diluted 1:10 with Dnase free water and was added to Rox diluted 1:10 with formamide. These products were submitted for fragment analysis and assessed on GeneMapper® software. No sequences were derived from the nuclear region, ITS1. No significant variation was detected in the chloroplast spacers but some preliminary geographical variation was shown through microsatellites stm200 and stm49. Interbreeding between close geographical populations was observed, however distinctive alleles were present across large distances. In order for conclusive evidence for the population genetics to be determined, more microsatellite markers would have to be assessed.

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